Upgrade your windows from XP to VISTA
they are offering 5 types of installation wich you can check out from here and they are:
1-Ultimate
2-Home Premium
3-Home Basic
4-Business
5-Enterprise: Designed to significantly lower IT costs and risks, Windows Vista Enterprise meets the needs of large, global organizations with complex IT infrastructures
Upgrading to Windows Vista with a clean install means that you should use Windows Easy Transfer to automatically copy all your files and settings to an extra hard drive or other storage device, and then install Windows Vista. After the installation is complete, Windows Easy Transfer will reload your files and settings on your upgraded PC. You will then need to reinstall your applications.
To upgrade your windows Click here to Download Windows Vista Upgrade Advisor.
The Windows Vista Upgrade Advisor will help you to determine if your Windows XP-based PC can run Windows Vista. You can also use the Upgrade Advisor to determine if your Windows Vista-based PC is ready for an upgrade to a more powerful edition of Windows Vista
This small software tool will scan your computer and create an easy-to-understand report of all known system, device, and program compatibility issues, and recommend ways to resolve them. Upgrade Advisor can also help you to choose the edition of Windows Vista that best fits the way you want to use your computer.
Just download, install, and run the Windows Vista Upgrade Advisor
PS: i didn't upgrade my windows yet cause Windows Vista needs a specific kind of high quality hardware that i don't have and a huge space in the hard disk.